v1_articles_controller.rb

module Api
  module V1
    class ArticlesController < ApplicationController
      def index
        articles = [
          { id: 1, name: 'The Things' },
        ]
        render json: articles
      end
    end
  end
end

v2_articles_constroller.rb

module Api
  module V2
    class ArticlesController < ApplicationController
      def index
        articles = {
          articles: [
            { id: 1, title: 'The Things' },
          ],
        }
        render json: articles
      end
    end
  end
end